Fit For: Our 3 1/2” Diesel Fuel Cap has a special thread and will only work on select compatible Kenworth Truck Tanks Attention: The Diesel Fuel Cap is non locking and for diesel tanks marked ULTRA LOW SULFUR DIESEL and LOW SULFUR DIESEL. This cap is not vented, your fuel tank must be vented SIZE: This Non-Locking Fuel Cap inner diameter is 3.5" and out diameter is 4". Measure old fuel tank neck or cap to verify fitment first OEM Quality: This Diesel Fuel Tank cap is real 100% aluminum casted, has a 8.0" chain and 6.5" bail which is made stainelss steel After-Sales Service: We sincerely appreciate the purchase of our 3.5" Diesel Fuel Cap For Kenworth Trucks. If you have any quality problems, we will reply to you within 24 hours wholeheartedly. We value your shopping experience Diesel Fuel Cap for Kenworth Trucks 3 1/2” Non-Locking, Non-Vented, Solid, for Ultra Low Sulfur Fuel Tanks